state police say adam lanza used several clips on a semi-automatic rifle to shoot the 26 victims at sandy hook elementary. >> these mass killings have to stop and we have to do everything we can. it will include looking at how many bullets do you need in a magazine in a semi-automatic weapon. >> on "meet the press," david gregory asked the nra's chief spokesman, why not bring back the ten-year ban that expired in 2004. >> i don't believe that's going to make one difference. there are so many different ways to evade that. you had that for ten years when goin feinstein passed that in '94. columbine occurred right in the middle of it. it didn't make any difference. >> the prospect of a ban on macks or assault weapons had people in atlanta standing in line for more than an hour at a gun show. customers at this shooting ranging in arizona say those weapons are widely used by sports cnn guys that shoot clays, guys that shoot trophy animals, a lot of them are done with semi-automatics. >> a group representing mothers says it will fight hard for a ban. >> 80 million moms are not going to let the